It has long been desirable to have a portable hand warmer that is economical of fuel and capable of providing heat at both higher and lower levels. The present invention relates to such a portable heater and has for one object a provision for dual fuel burning capabilities. It is first possible to provide heating at a relatively low heat level through the use of a heating medium of a semi-solid type such as canned heat or "Sterno". The second source of heat which optionally may be included in the heater is provided by charcoal, coal or other solid fuel which is placed in the upper portion of the heater on the grate separating such portion from the lower portion. In the operation of the heater, a slow-burning long-lasting heat of higher level is provided when the upper solid fuel is ignited.
It is further possible to provide almost instant heat for hand or body warming by igniting the semi-solid fuel and allowing it to burn within the lower portion of the heater while being held in an easily removable but securely clipped arrangement in the base.
When it is desired to change over from the lower heat level operation, solid fuel is introduced in the upper portion on top of the grate, the semi-solid fuel such as canned heat or "Sterno" is then used as the igniting agent for the charcoal. At this point the portable heater produces instant heat and at the same time the charcoal or other solid fuel begins its own burning cycle. When the charcoal or other solid fuel is properly ignited, the semi-solid fuel is removed from its clipped position in the base and readily extinguished keeping it available to be used again as a starting agent for the charcoal or other solid fuel. It will be understood that at least two or three hours of reliable heat can be obtained from a small size heater employing charcoal or other solid fuel positioned in the upper portion above the grate.
It will likewise be seen that this invention has the capability of transporting the charcoal or other solid fuel preset on the grate and held in place when the upper lid is in a closed position. Also it is possible to transport the heater including the igniting source of semi-solid fuel held in position by its own retaining clips mounted in the lower portion of the heater. Thus a lightweight, compact, easily operable heating package is provided. It is also important to note that this invention eliminates the requirement for starting fluids or other highly inflammable materials or their being carried upon the person of the user.
The present invention thus provides a heat source that is high in the volume of heat produced yet relatively small in size and weight and exceedingly portable. The fastening means for the lid of the portable heater may be a snap-ring which allows easy engagement or disengagement of the top depending on the operation desired. The solid or air-tight top plate when it is raised allows for a maximum air circulation and for maximum heat production.
A belt attachment ring connected to the upper part of the heater to aid in its carrying. In conjunction with the improved mobility, the belt loop further serves as a means for handling the heater when it is hot.
Prior art arrangements are known for heaters which are relatively portable and incorporate solid or semi-solid fuels. One such type of heater is shown and disclosed in L. B. Skinner U.S. Pat. No. 1,482,586 issued on Feb. 5, 1924, for "Orchard Heater". The heater disclosed in that application however requires the use of an inflammable fluid for igniting a solid fuel and does not have the dual heating level capability of the present invention.
A further similar device is shown and described in R. N. Frank U.S. Pat. No. 2,174,824 issued on Oct. 3, 1939, for "Portable Cooker". The patent discloses a cooker which uses as its heat source a canned heat or "Sterno". The arrangement disclosed does not include two separated portions adapted to provide higher and lower levels of heating through the use of an additional solid fuel as well as the Sterno fuel.
A further portable heating stove is shown in J. M. Higman U.S. Pat. No. 2,488,014 issued on Nov. 15, 1949, for "Sheet Metal Heating Stove". This patent shows a stove using solid fuel such as charcoal or briquets which is lighted by stuffing paper or rags saturated with a flammable fluid in order to ignite. The heating stove does not have the capability of dual level heat operation nor does it have the arrangement afforded by the present invention for easily incorporating or removing the receptacle for semi-solid fuel at the base of the heater.
A still further portable stove is disclosed and claimed in W. B. Seeley U.S. Pat. No. 936,482 issued on Oct. 12, 1909, for "Portable Stove". This patent discloses a rather simple arrangement of lamp plus enclosing shell in which the heat source is of a single heat level and originates with a lamp incorporated in the base of the stove.
A final prior art disclosure of a portable stove is included in T. E. Taylor U.S. Pat. No. 1,342,072 issued on June 1, 1920, for "Portable Stove". This patent includes a single enclosing shell with a grate for holding solid fuel content for heating operation. Again there is no disclosure of a dual heat level stove of the type shown and described in the instant application.